IEEE 1149.1 Test Access Port (JTAG)
MCF52110 ColdFire® Integrated Microcontroller Reference Manual, Rev. 1
Freescale Semiconductor
28-5
Preliminary
28.3.3
Bypass Register
The bypass register is a single-bit shift register path from TDI to TDO when the BYPASS instruction is
selected.
28.3.4
JTAG_CFM_CLKDIV Register
The JTAG_CFM_CLKDIV register is a 7-bit clock divider for the CFM that is used with the
LOCKOUT_RECOVERY instruction. It controls the period of the clock used for timed events in the CFM
erase algorithm. The JTAG_CFM_CLKDIV register must be loaded before the lockout sequence can
begin.
28.3.5
TEST_CTRL Register
The TEST_CTRL register is a 3-bit shift register path from TDI to TDO when the
ENABLE_TEST_CTRL instruction is selected. The TEST_CTRL transfers its value to a parallel hold
register on the rising edge of TCLK when the TAP state machine is in the update-DR state.
28.3.6
Boundary Scan Register
The boundary scan register is connected between TDI and TDO when the EXTEST or
SAMPLE/PRELOAD instruction is selected. It captures input pin data, forces fixed values on output pins,
and selects a logic value and direction for bidirectional pins or high impedance for tri-stated pins.
IR[4:0]: 0_0001 (IDCODE)
Access: User read-only
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10
9
8
7
6
5
4
3
2
1
0
R
PRN
DC
PIN
JEDEC
ID
W
Reset
See note
0
1
1
1
0
1
See note
0
0
0
0
0
0
0
1
1
1
0
1
1
The reset values for PRN and PIN are device-dependent.
Figure 28-3. IDCODE Register
Table 28-4. IDCODE Field Descriptions
Field
Description
31–28
PRN
Part revision number. Indicate the revision number of the device.
27–22
DC
Freescale Design Center number.
21–12
PIN
Part identification number. Indicate the device number.
11–1
JEDEC
Joint Electron Device Engineering Council ID bits. Indicate the reduced JEDEC ID for Freescale (0x0E).
0
ID
IDCODE register ID. This bit is set to 1 to identify the register as the IDCODE register and not the bypass register
according to the IEEE standard 1149.1.